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Hybrimune Hybridoma Production System
Publication 015-1010191 Rev 4.0 • www.btxonline.com
Electrofusion
The process of electrofusion has three steps:
1. Cell alignment and compression
2. Fusion
3. Stabilization
The first step is to align the cells and then compress using special
electric fields. The Hybrimune System uses an alignment and
compression technique called dielectrophoresis. The process of
manipulating matter using electric fields has been discussed for
hundreds of years. The process of using non-uniform electric
fields has been used for a number of applications in chemistry,
physics, biology and engineering for several decades (Pohl,
Dielectrophoresis, Cambridge University Press, 1978). Cell
electrofusion was described by Zimmerman in a 1982 paper
(Zimmerman and Vienken, J. Membrane Biology 67, 165-182,1982).
This section covers the basic physics of dielectrophoresis which
includes the chamber in which the cells are fused. Page 37 presents
more detailed information on the special waveforms used.
Cell alignment (Dielectrophoresis)
The first step is in electrofusion is to bring the cells together
and compress using special electric fields. This is a critical and
complex step. Cells have a net zero charge but do have a local
negative charge on the surface which acts as a repelling force.
The Hybrimune System uses an alignment technique called
dielectrophoresis that applies a force to overcome the surface
charge. From basic physics we know that the force on a charged
particle in an electric field is:
FORCE = ELECTRIC FIELD X CHARGE
Therefore if a cell, which has a net charge of zero, is placed
between two parallel flat electrodes which produce a uniform field,
the force applied to the cell is zero. However, there are charges
inside the cell such as salt ions. A force is applied to these charges
and they will move until stopped, in this case by the cell membrane
(an insulator) creating a dipole inside the cell. In a uniform field
the force applied is equal and opposite and the cell will not move.
However, if a non-uniform field is used the forces are not equal and
opposite and the cell will move in the direction of the highest field
intensity (see Figure 11).
If there are a number of cells in the non-uniform field, then the
cells will line up due to the attraction of unlike charges as shown
in Figure 12.
Uniform Field
No Movement
Figure 11: Uniform and Non-Uniform Fields
Figure 12: Cell Alignment
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Non Uniform
Field Movement
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Cell Electrofusion Tutorial